PROCESS FOR MANUFACTURE OF LOW-VISCOSITY INDEX OILS Russian patent published in 2002 - IPC

FIELD: petroleum processing. SUBSTANCE: lube distillate fraction 280-400 C is refined with N-methylpyrrolidone. Refined oil is subjected to extensive deparaffination as follows. Primary gatch is deparaffinated at temperatures minus 32-34 C in three filtration steps to give (i) oil with freezing point of minus 15 C and viscosity index at least 130 and (ii) paraffin with oil level no higher than 2.3%. Fine deparaffination is carried out preferably at temperatures minus 62-52 C to give base oil with freezing point from minus 55-45 C and primary gatch with 30-40% oil level. EFFECT: increased efficiency of petroleum processing. 4 cl, 1 tbl, 14 ex